1. Field of the Invention
The present invention relates to a changeable lens barrel of a form that changes to a more retracted state during non-photographing than during photographing and changes to a more extended state during the photographing than during the non-photographing.
2. Description of the Related Art
A lens barrel applied to a photographing apparatus such as a camera has been configured by various members such as a photographing optical system including a plurality of optical lenses, a plurality of lens barrel members for holding the photographing optical system and moving the photographing optical system in an optical axis direction, a driving member and the like that drive a part of the plurality of lens barrel members, and a diaphragm mechanism.
In such a lens barrel, a zoom lens barrel including a photographing optical system configured to be variable in magnification to enable a continuous change of a focal length is widely spread. In the zoom lens barrel, the photographing optical system is configured using a large number of optical lenses in order to configure the zoom lens barrel to be variable in magnification. Therefore, a dimension in the optical axis direction in a use state tends to increase. That is, the zoom lens barrel normally changes to an extended state when set in a photographable use state and is configured be telescopic according to zoom operation at this point.
Therefore, in the zoom lens barrel in the past, in order to improve portability during non-photographing (during nonuse) when photographing is not performed, various zoom lens barrels of a so-called collapsible type configured to be capable of setting an entire length in an optical axis O direction in a shorter state (a collapsed state) than in an extended state during use have been proposed by, for example, Japanese Patent Application Laid-Open Publication No. 2010-286789 and have been generally put to practical use.
The zoom lens barrels of the collapsible type disclosed in Japanese Patent Application Laid-Open Publication No. 2010-286789 and the like are configured in a three-stage extendable type and configured such that both of a zoom operation ring and a focus operation ring are exposed to a barrel outermost portion when the zoom lens barrels axe changed to the collapsed state.
In recent years, in photographing apparatuses such as a camera (e.g., a digital camera and a video camera), a photographing apparatus equipped with a zoom lens barrel including an optical zoom function is spread to public. The zoom lens barrel of this type has an advantage that it is possible to easily enjoy a change in an angle of view of an image that can be photographed by a continuous magnification function. On the other hand, since a photographing optical system is configured by a group of a plurality of optical lenses, an entire length in a direction along an optical axis tends to be large.
In the photographing apparatuses such as the camera in the past, a reduction in a size of the apparatuses is always demanded in order to improve portability. For example, in the photographing apparatuses in the past, various zoom lens barrels including a so-called collapsible mechanism of a form including a mechanism that changes to a more retracted state during non-photographing than during photographing and configured to change to a more extended state during the photographing than during the non-photographing have been proposed by Japanese Patent Application Laid-Open Publication No. 2-25815 and the like and have been generally put to practical use. By applying such zoom lens barrels including the collapsible mechanism, it is possible to realize a reduction in thickness in an optical axis direction of photographing apparatuses such as a camera during the non-photographing, that is, during carrying. Therefore, it is possible to improve portability of the photographing apparatuses such as a camera.
On the other hand, in the photographing apparatuses such as the camera in the past, various proposals have also been made concerning a photographing apparatus of a so-called lens replaceable type configured to enable, by configuring a lens barrel to be detachably attachable to a camera main body, a user to select a desired lens barrel from a plurality of kinds of lens barrels, replace the lens barrel with the desired lens barrel as appropriate, and use the desired lens barrel and a replaceable type zoom lens barrel applied to the photographing apparatus and have been generally put to practical use.
As the replaceable type zoom lens barrel in the past adopting the collapsible type, there is a zoom lens barrel of a form in which, when the zoom lens barrel is changed to a collapsed state, annular operation members such as a zoom ring and a distance ring are disposed on a fixed portion exposed to an outside. In the case of this form, the operation members such as the zoom ring and the distance ring are set in a state in which the operation members do not move in an optical axis direction with respect to the fixed portion and to be turnable around the optical axis.
In a replaceable zoom lens barrel and the like disclosed by, for example, Japanese Patent Application Laid-Open Publication No. 10-20176, the replaceable zoom lens barrel and the like are configured such that rotation resistance of a zoom ring is larger in a collapsing operation region than in a zoom operation region and is configured such that a rotation operation force in the collapsing operation region is larger than a rotation operation force during attachment and detachment of the zoom lens barrel to and from a camera main body. With this configuration, only the annular operation members do not rotate when the zoom lens barrel is attached to and detached from the camera main body. The zoom lens barrel can have operability and attaching and detaching properties.
The present invention provides an optical apparatus in which, in a lens barrel fixed to the optical apparatus or the like, while adopting a collapsible mechanism that changes to a more retracted state during non-photographing than during photographing and changes to a more extended state during the photographing than during the non-photographing, the lens barrel with the entire apparatus reduced in a size when the lens barrel is changed to a non-photographing state (a collapsed state) is fixed and provide a replaceable lens barrel configured not to hinder attaching and detaching properties and to be capable of securing satisfactory operability during the photographing even if the replaceable lens barrel is reduced in a size to be capable of being retracted in length in a replaceable lens barrel.